A mail-tag has a corresponding form-tag; when an email is composed, a mail-tag in the email template is replaced with the user input value that comes through the input field represented by the corresponding form-tag.

Contact Form 7 provides several kinds of user-input validation by default, including:

• Is a required field filled in?
• Does an email field have an email address in the correct format?
• Is an uploaded file in an acceptable file type and size?

You can also add your own custom validation.

The previous recipe illustrated how you can add custom form-tags simply. In this recipe, you’ll learn how to retrieve values from a form-tag and use those values in the HTML output in a form.

This is the first entry in a series of articles to help developers customize Contact Form 7.

The first topic is expanding Contact Form 7’s form-tags. As you probably know, form-tags are code in a specific format within square brackets, usually representing form controls like text input fields and submit buttons. Currently, Contact Form 7 supports 30 different types of form-tags by default.